PARENT SESSION
Symposium 19: The Role of Plant-Microbe Feedbacks in Plant Invasions
Organized by: K Reinhart and R Callaway
Thursday, August 7. 1:30 PM to 5:00 PM, SITCC Oglethorpe Auditorium.
Introduction to plant-microbe feedback in plant invasions and invasive non-native trees escaping from soil pathogens.
Reinhart, Kurt*,1, Packer, Alissa2, Clay, Keith2, Van der Putten, Wim3, Callaway, Ragan1, 1 University of Montana, Missoula, MT2 Indiana University, Bloomington, IN3 Netherlands Institute of Ecology, Heteren, The Netherlands
ABSTRACT- Soil biota are known to affect natural plant communities and may also affect the impact of invasive non-native species. We tested the sensitivity of invasive trees (Acer negundo, Acer platanoides, and Prunus serotina) to the resident soil biota in their native and non-native ranges and related this to the spatial aggregation of conspecifics in individual ranges. Overall, there was a general negative effect of the soil biota on seedling survival/growth of all three species within their native ranges; however, A. negundo, near the fringe of its natural distribution, was not affected by soil biota. In the non-native range, the soil biota had a positive effect on the growth of P. serotina seedlings. Moreover, A. platanoides seedlings within their non-native range were positively effected by the soil biota from heterospecifics but negatively effected by the soil biota from conspecifics. Acer negundo, within its non-native range, was not affected by the soil biota associated with either conspecifics or heterospecifics. The negative effects of the soil biota within the native ranges correspond with sparse aggregations of conspecifics. In contrast, the soil biota within the non-native ranges tended to facilitate the growth of seedlings and corresponded with dense aggregations of conspecifics. Our results suggest that negative soil feedbacks in native ranges may help to maintain forest diversity while the positive soil feedbacks in the non-native ranges may help to facilitate invasion by releasing invasive trees from belowground enemies.
Key words: soil feedback, facilitation, invasive species, enemy release hypothesis